Tuner linkage



March 6, 1951 G. F, BEHRINGER TUNER LINKAGE Filed July 2, 1949 HMHHHEPEPatented Mar. 6, 1951 TUNER LINKAGE Grover F. Behringer, Defiance, Ohio,assignor, by ,mesne assignments, to All Star Products, Inc.,

Defiance, Ohio, a corporation of Ohio Application July 2, 1949, SerialNo. 102,759

This invention relates to mechanical linkage particularly for aninductive-type tuner wherein it is desirable to slide a powdered ironcore in a tube by rotation of a tuning knob or the like.

One object of the invention is to provide linkage between the powderediron core and the shaft of a tuner which is comparatively simple andvery inexpensive to manufacture so that the linkage can be made for afew cents, the parts being so designed that accuracy of movement of thecore in relation to rotation of the shaft is had even though the partsare made by a stamping process which eliminates all machiningoperations.

Another object is to provide a tuner linkage which can be added to astandard plate-type variable condenser or similar tuner and whichlinkage includes a minimum of parts; mainly a yoke that can be sprung onto the frame of the plate-type condenser, a cam to be secured to thecondenser shaft and a connector plate from which coil springs extend tothe iron cores in a simple manner, a single spring being used to holdthe parts in proper operative position and return the yoke in onedirection for holding a cam follower of the yoke against a cam that isused to operate the linkage.

Still another object is to provide a yoke with a pair of pivot pointsbent therefrom, the yoke being arranged to spring over a plate-typecondenser frame and the pivot points to enter drilled or punchedopenings therein, the yoke having v-notches in which a connecting plateis engaged by a return spring and the connecting plate having a pair offingers sheared therefrom and bent to a position permitting a coilspring to be interposed between the fingers and the plate in such mannerthat the spring is held against longitudinal movement but may be rotatedfor adjusting the slug toward or away from the yoke.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mytuner linkage, whereby the objects contemplated are attained, ashereinafter more fully set forth, pointed out in my claims andillustrated in the accompanying drawings, wherein:

Figure 1 is a plan view showing (in light lines) parts of a standardvariable plate-type tuner or condenser and showing in shaded lines aninductance-type tuner added thereto and my tuner linkage for connectingthe cores of the inductance-type tuner for operation from the shaft ofthe plate-type condenser.

Figure 2 is a front elevation thereof" looking 11 Claims. (Cl. i l-10.9)

upwardly at Figure 9, a portion of the one of the inductance tuner unitsbeing shown in section. Figure 3 is an end elevation looking toward theleft at Figure 2.

Figure 4 is a perspective view of a yoke of my tuner linkage.

Figure 5 is a perspective view of a connection plate thereof.

Figure 6 is a plan view of a plate-type condenser frame and the yoke andplate of Figures 4 and 5 to show the association of the yoke with thecondenser frame.

Figure 7 is a vertical sectional view on the line 1- of Figure 2. T

Figure 8 is an enlarged sectional View on the line 8-B of Figure 3.

Figure 9 is a further enlarged detail view on the line 99 of Figure 1;and

Figure 10 is an enlarged sectional view on the line l0-l 0 of Figure 3.

On the accompanying drawing I have used the reference numerals l2 and I4to indicate the base and end flanges of a standard plate-type variablecondenser and Hi the shaft thereof. The shaft IB is usually providedwith some suitable type of control knob such as 18 and, as well known,this knob coacts with a dial indicating frequencies or wave lengths foran AM type of radio tuner. The stationary condenser plates supported inthe frame l2l4 and the movable condenser plates supported by the shaft16 have been omitted as they form no part of my present invention.

When a radio set is designed forFM also, or When an AM radio isconverted to include FM, usually inductance-type tuners or variablecapacitors are added which are of the powdered iron core type asinductive tuning is better for audio frequencies because there is lesselectrical loss. These inductive tuners are usually in the form of atube 28 of insulating material wound with a metal ribbon 22 and havingtherein a slidable powdered iron core or core 24. To support the tubes20, I provide a supporting plate 26 which may be secured to thecondenser frame |2l4 by screws 28 and which is provided with openingsthrough which the tubes 20 extend as shown in Figure 7, the tubes beingsuitably secured therein in any desired manner.

For sliding the cores 24 in the tubes 20, I rovide my tuner linkagewhich will now be described. It comprises a yoke formed of sheet metaland having a cross-piece 30 and a pair of arms 32 and 34. These arms areprovided with pivot points 36 bent from the plane thereof in an obviousmanner. The cross-piece 30 is provided with a finger 38, the arms areprovided with V-notches 40 and a cam follower 42 is pivoted at 44 to thearm 32 all as clearly shown in Figure 4.

The yoke 3ll--32-34 has an initial shape shown particularly in Figure 6(solid lines), the arms 32 and 34 being bent to a position where theyconverge. The right-hand ends of the arms, it is noted, are closertogether than the outer surfaces of the flanges l4 of the condenserframe. These flanges are provided with open.- ings 46 punched or drilledtherein (punching of course being a more economical operation toperform) and during assembly the arms are merely sprung apart to thedash-line position shown in Figure 6 so that the pivot points 36 clearthe flanges l4 whereupon the yoke may be lowered until the pivot pointsregister with the openings and then permitted to spring inwardly to thedotted line position which is the finally assembled position shown alsoin Figure 1. The resiliency of the arms 32 and 34 thereupon causes thepoints 36 to snugly engage in the openings 46 with three or four-pointcontact so that all sloppiness or lost motion of the pivot joints isentirely eliminated.

I provide the cores of iron 24 with coil springs 48 which may be moldedin the upper ends of the cores during their formation to provide asecure connection between each core and its spring. These springs aremade of approximately the proportions shown in Figure so that they areopen between the coils approximately the diameter of the spring wireused to form them and I provide a connection from the springs to theyoke in the form of a connection plate 50.

The connection plate 58 has a pair of fingers 52 to engage in thenotches 40 of the yoke 383234 and a pair of fingers 54 sheared and benttherefrom to resiliently coact with the springs 48 in the manner bestshown in Figure 10 so that an effective connection is had which servesalso as a screw threaded connection for adjustment purposes as rotationof the spring will adjust it upwardly or downwardly relative to theplate 58 depending on the direction of rotation. Since the finger 54 issheared from the plate 58, there will be slight edges 55a and 54a drawnoppositely on the opening from which the fingers are cut and on thefingers themselves as shown in Figure 10 and these edges are sufficientto engage between the coils of the spring without the necessity ofproviding a special nut or the like as a connecting means. This ofcourse contributes to economy of manufacture.

The connection plate 50 is provided with a perforation 56 adapted toloosely receive the finger 38 of the yoke cross-piece 30 to retain theplate in position once it is assembled. To accomplish assembly, theplate is bowed to the dotted position shown in Figure 6 whereupon thefingers 52 may be engaged in the notches 48 and then the plate 50 may bereleased. It. thereupon straightens to its full line position due to itsinherent tendency to remain straight Whereupon the plate 58 is retainedagainst dislodgment of its fingers 52 from the notches 48 except whenthe plate is purposely sprung again for removal purposes.

On the shaft l6 of the condenser, I provide an eccentric-shaped cam 58having a hub. For economy of manufacture this hub may be a press fit,thus eliminating a set screw or other additional fastening device andthe shaft may be fluted to eliminate all possibility of rotation of thecam relative to the shaft once it is pressed in position.

The yoke is designed to be operated by the cam 58 for which purpose, ofcourse, the follower 42 engages the periphery of the cam. To insure suchengagement I provide a spring 62 connected to a finger 64 sheared andbent upwardly from the supporting plate 62 and a series of openings 66in the connection plate 50. This single spring accomplishes, in additionto holding the follower 42 against the cam 58, the function of holdingthe fingers 52 in the notches 48 without any lost play and the furtherfunction of swinging the plate to its best aligned position with respectto the tubes 28 by always tending to line up the plate withthe finger 84as shown in the two positions illustrated in Figure 2. This arrangementprovides for a minimum of bending in thes'prings 48 at the upper end ofthe cores 24 and at the connection plate 50 and its fingers 54.

At the same time, the springs 48 (being formed of open coils) aresufiiciently flexible to permit proper sliding of the cores 24 in thetubes 28 without binding and thus accuracy of longitudinal position ofthe core in the tube with respect to the rotary position of the knob I8is assured. Of course there is some longitudinal flexing of the springswhich is greater the more friction there is between the cores and thetubes, but I have found this negligible in a tuner of the kind disclosedwhere a dial is associated with the knob l8 and any off-tuning conditioncan be readily corrected by the operator without a toocritical necessityof matching the knob pointer with the markings on the dial.

Where my tuner linkage is provided in connection with an AM-FM radioset, the disclosed arrangement is suitable whereas it is obvious that ina strictly FM receiver, a suitable shaft, particularly for the FM tunermay be provided as the tuner linkage is adaptable for generalapplication as well as a combination application with an AM radio.Usually in a combination radio, separate AM and FM dials are providedfor the single knob I8 and a suitable switch used to connect either theplate-type condenser in the AM circuit or the inductance-type tuner inthe FM circuit.

Due to the follower 42 being on only one of the arms of the yoke38-32-34, there is some slight twisting of the yoke 30 but I have foundthis negligible and that it can be compensated for to some extent byconnecting the spring 62 at an angle as shown so that it has more effecton the arm 32 than on the arm 34. At the same time the parts can beinexpensively stamped from relatively light sheet metal withoutprohibitively sacrificing accuracy of core position in relation to knobposition.

Some changes may be made in the construction and arrangement of theparts of my tuner linkage without departing from the real spirit andpurpose of my invention, and it is my intention to cover by my claimsany modified forms of structure or use of mechanical equivalents whichmay be reasonably included within their scope.

I claim as my invention:

1. In a tuner linkage of the character disclosed, a yoke, each armthereof having a pivot point, said pivot points being directed towardeach other, said yoke being adapted for pivotal connection to a pair ofspaced elements having perforations therein, said arms being outsidesaid spaced elements and biasedtoward each other to resiliently engagesaid pivotipoints said perforations, a follower pivoted to said yoke, acam for coaction therewith, spring means to urge sa1d yoke in adirection for said follower to engage said cam, and means for connectingsaid yoke to coil springs extending from tuner cores or the like.

2. In a tuner linkage, a yoke, each arm thereof having a V-shaped pivotpoint, said yoke being adapted for pivotal connection to a pair ofspaced elements having perforations therein, said arms being undertension to enter said points in said perforations as far as they will goin response to such tension to eliminate i play in the pivots for theyoke, a follower on said yoke, a cam for coaction therewith, springmeans to urge said yoke in a direction for said follower to engage saidcam, and means for connecting said yoke to coil springs extending fromtuner cores or the like.

3. Tuner linkage of the character disclosed comprising a yoke, a pair ofspaced elements to which the arms of said yoke are pivoted, a followercarried by said yoke, a cam for coaction therewith, spring means to urgesaid yoke in a direction for said follower to engage said cam, and meansof connection between said yoke and tuner cores or the like, said meansof connection comprising fingers extending from the cross piece of saidyoke and springs screw-threadedly engaged between said fingers and saidcrosspiece for axial adjustment of said springs relative to said crosspiece by rotation of said springs relative to said fingers.

4. Tuner linkage of the character disclosed comprising a yoke, the armsthereof being pivotally mounted, a cam follower pivoted to one arm ofsaid yoke, a cam engaged thereby, a support, tuner sleeves supportedthereby, cores slidable in said sleeves, the arms of said yoke beingprovided with V-notches, a connection plate having fingers pivotedtherein, a finger extending from the cross piece of said yoke, saidconnection plate having an opening loosely receiving said finger, saidconnection plate having fingers, coil springs screw-threadedly engagedbetween said last fingers and said connection plate and extending .tosaid cores, and a spring connection between said plate and said supportto align the plate with said sleeves, to keep said fingers in saidnotches and to retain such cam follower against said cam.

5. Tuner linkage of the character disclosed comprising a yoke, the armsthereof being pivotally mounted, a cam follower pivoted to one arm ofsaid yoke, a cam engaged thereby, a support, tuner sleeves supportedthereby, cores slidable in said sleeves, the arms of said yoke beingprovided with V-notches, a connection plate having fingers pivotedtherein, said connection plate having fingers extending therefrom, coilsprings screw-threadedly engaged with said last fingers located betweenthem and said connection plate and extending to said cores and a springconnection with said plate to align it with said sleeves, to keep saidfingers in said notches and to retain such cam follower against saidcam.

6. In a tuner linkage, a yoke, one arm thereof having a cam follower, acam coacting therewith, each arm of said yoke having a pivot point, saidyoke being adapted for pivotal connection to a pair of spaced elementshaving perforations therein, said arms being under tension to engagesaid pivot points in said perforations, the arms of said yoke beingprovided with V-notches,

a connection plate having fingers pivoted there in, a finger extendingfrom the cross piece of said yoke, said connection plate having anopening loosely receiving said finger, said connection plate beingprovided with fingers, coil springs screw-threadedly engaged betweensaid last fingers and said connection plate and extending to inductancetuner cores or the like, and a spring connection with said plate toalign it with the sleeves that slidably receive said cores, to keep saidfingers in said notches, and to retain such cam follower against saidcam.

7. In a tuner linkage, a yoke, onearm thereof having a cam follower, acam coacting therewith, each arm of said yoke having a pivot point, saidyoke being adapted for pivotal connection to a pair of spaced elementshaving perforations therein, the arms of said yoke being provided withV-notches, a connection plate having fingers pivoted therein, saidconnection plate having other fingers extending therefrom, coil springsscrew-threadedly mounted between said last fingers and said connectionplate and extending to inductance tuner cores or the like, and a springconnection with said plate to align it with the sleeves that slidablyreceive said cores, to keep said fingers in said notches, and toretain'such cam follower against said cam.

8. In a tuner linkage, a yoke, each arm thereof having a pivot point,said yoke being adapted for pivotal connection to a pair of spacedelements having perforations therein, said arms being biased toward eachother with said pivot points entered in said perforations, a follower onsaid yoke, a cam for coaction therewith, and means of connection betweensaid yoke and the cores of an inductance tuner comprising coil springs,extending from said cores, a connection plate with which said'springsare adjustably screw-threadedly connected, notch and finger engagementbetween said connection plate and said yoke, and a spring connected withsaid connection plate substantially in alignment with sleeves for saidcores.

9. Tuner linkage of the character disclosed comprising a yoke, each armthereof having a pivot point, said yoke being adapted for pivotal.

connection to a pair of spaced elements, a cam follower mounted on saidyoke, a cam for coaction therewith, spring means to urge said yoke in adirection for said follower to engage said cam, and means of connectionbetween said yoke and the cores of an inductance tuner comprising coilsprings extending from said cores, a connection plate with which saidsprings are connected, and notch and finger engagement between saidconnection plate and said yoke, said spring means being connected withsaid connection plate to retain said notch and finger engagement inproper coacting relation,

10. In a tuner linkage, a pivotally mounted yoke, a follower thereon, acam for coaction with said follower, and means of connection betweensaid yoke and the cores of an inductance tuner or the like comprisingcoil springs extending from said cores, a connection plate with whichsaid springs are screw-threadedly connected, notch and finger engagementbetween said connection plate and said yoke, and a spring connected withsaid connection plate to retain such engagement and engage said followerwith said cam.

11. In a tuner linkage of the character disclosed, a yoke, each armthereof being pivoted to a support, a follower pivoted to said yoke, acam for coaction therewith, spring means to 7 in'gesaid yoke in adirectionfor said follower to engage said cam, and means of connectionbetween said yoke and the cores of a tuner comprising coil springs and aconnection plate connected with them and pivoted to said yoke.

GROV'ER F. BEHRINGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

8 UNITED STATES PATENTS Name Date Cohen et a1. May 20, 1941 Benton eta1. Sept. 2, 1941 Pifer Sept. 13, 1949 FOREIGN PATENTS Country DateGreat Britain Feb. 15, 1934

